The present invention relates to a pulley press controlling apparatus using an elastic member in which a pressurizing force and an elastic force corresponding thereto are always simultaneously applied from outside to a frictional transmission surface between a pulley and a belt transmission in a continuously variable speed transmission or a constant speed ratio transmission to stably maintain the accuracy of the elastic press and so on over a long period of time.
The idea for directly and hydraulically supplying and controlling an external pressurizing force to a secondary pulley having a belt transmission member held between two disks is well-known from, for example, such as Japanese Patent Application Laid-Open No. Hei 9 (1997)-217819 or U.S. Pat. No. 5,180,339. The greatest feature of prior art of this kind lies in that a hydraulic pressurizing device and an elastic member are pressed and disposed in parallel to each other with respect to a secondary pulley disk to be pressed. That is, because of the parallel disposition, respective pressurizing means directly press the secondary pulley independently. This has a decisive defect with respect to the frictional transmission for the following reason. That is, the horse power P fed by the pulley to the load is normally expressed by the following equation between the revolution number N and the torque T:
P[W]=1.027xc3x97N[rpm]xc3x97T[kgm]xe2x80x83xe2x80x83(1)
Accordingly, it is necessary for the transmission of a fixed horse power Pc to reduce a torque T of a belt when the revolution number N increases, and conversely increase the torque T when the revolution number N reduces. In the prior art, inverse proportional pressure is applied to the secondary pulley by a hydraulic pressurizing device, but since there is present no elastic force in fluid pressure itself, in control of internal pressure of a hydraulic valve, an elastic member is used to suppress the disturbance of internal pressure generated every change-over or switching.
Then, the using state of the elastic member will be mentioned referring to FIG. 6. Even if the hydraulic pressurizing device should realize the inverse characteristic A between the pressurizing force to the secondary pulley and the revolution number, the elastic force of the elastic member merely comprises the direct proportional characteristic D. Accordingly, this means that the elastic force is applied to the pressurizing force merely by a point of intersection F between the characteristics A and D, but in points other than the point of intersection F, the elastic force rarely contributes to transmission. The fact that the elastic force is not present in the frictional transmission surface despite the presence or absence of variable speed indicates that the momentary return into the stable transmission caused by the self settling function for pressurizing and absorbing shock vibrations between the pulley and the belt and the automatic aligning function fails to be achieved. Therefore, since in the frictional transmission surface, the state of surplus press or lack in press is repeated every disturbance, there poses a disadvantage that consumption of the frictional surface is accelerated, resulting in disablement of transmission in a short period of time.
The present applicant has made a proposal, in Japanese Patent Application No. Hei 10 (1998)-321246, in which an elastic pressurizing force generated by pressurizing a compression device and an elastic device in series with each other is applied to a secondary pulley. However, positive application of the elastic force of the elastic member to the friction transmission causes an advantage and a disadvantage present simultaneously. The advantage includes stabilization of transmission for a long period of time, and high-speed control responsiveness. The disadvantage includes a huge dimension of and a large-size of the elastic member, disturbance of process accuracy in manufacture of compression displacement to pressurizing force, variation of pressurizing characteristic caused by deformation and deterioration in order to maintain repeated compression and high load compression, and ambient temperature. The huge dimension can be solved by measures such as the use of a special high load elastic member or the arrangement of the elastic member in a non-rotational state, but the disturbance of the elastic pressurizing force generated from the pressurizing device itself brings forth instability of direct frictional transmission and degeneration of efficiency. Accordingly, it has been strongly expected that the pressurizing force and the revolution number are applied to the elastic pressurizing device having the elastic member and the non-elastic pressurizing device using the negative measures for applying restoring compensation of an error in pressurizing force caused by manufacturing or use of high load and already generated to a proper value, and the positive measures for applying function adjustment for further accelerating and strengthening utility of an elastic member during transmission or during stoppage.
A fundamental solution of the present invention is to provide a pulley press controlling apparatus using an elastic member in which a pressurizing device always applies an elastic pressurizing force to a pulley, and always controls it to a predetermined desired pressurizing force selected value with the compensation of an error in pressurizing force of the elastic pressurizing force and/or the adjustment of pressurizing function to stably maintain and strengthen the utility function of the elastic pressurizing force of the elastic member in a long period of time.
According to a first aspect of the present invention, an error in pressure of an elastic pressurizing force caused by the manufacturing and processing accuracy of a pressurizing device having an elastic member and the peripheral temperature of installation and caused by the deformation and deterioration of the elastic member under the repeated compression or high compression for a long period of time is restored and compensated to always apply an elastic pressurizing force of high accuracy.
According to a second aspect of the present invention, a desired selected value of an elastic pressurizing force applied by an elastic member is applied with fine adjustment during transmission operation to forcibly change the efficiency of transmission or safety rate, or applied with extremely low reduction adjustment positively during stoppage of transmission to forcibly release or suppress the compression state for a long period of time to thereby apply strengthening adjustment of utility function of the elastic member substantially.
According to a third aspect of the present invention, restoring compensation of an error in pressure of an elastic pressurizing force and adjustment for strengthening a pressurizing force by forcibly reducing the pressurizing force selected value are combined so that operating information of restoring compensation is taken in at the time of the strengthening adjusting operation in the process of applying pressure to or releasing pressure from the elastic member to effect operation processing to newly execute pressure error compensation for variable speed or press control.
According to a fourth aspect of the present invention, when a pressurizing device operates in variable speed a pulley under non-elastic pressurizing force, an error in revolution number of a secondary pulley caused by a deformation and deterioration of belt dimension is compensated by the procedure similar to that taken for the error in pressurizing force.
According to a fifth aspect of the present invention, since a pulley added an elastic force controls an output torque based on a belt frictional force and a pulley added a non-elastic force controls an output revolution number, a control device provides operating instructions to the operating devices by dealing with various informations collectively and so simplicity and reliability of control manipulation are achieved.
It is a fundamental object of the present invention to provide a pulley press controlling apparatus using an elastic member, the apparatus including:
a pressurizing device for applying an elastic or non-elastic pressurizing force to a pulley; an operating device for operating said pressurizing device; a condition detector for knowing a detected value of a pulley pressurizing force or a pulley revolution number; and a control device for outputting, as a pressure operating instruction, a desired selected value of an elastic or non-elastic pressurizing force predetermined in a storage device in response to an input operating instruction, said control device having a processing unit for applying to the input operating instruction a compensation amount and/or an adjustment amount corresponding to a process deviation of said selected value and said detected value to convert and output it to said pressure operating instruction.
Further other object of this invention is that an elastic force supplying pulley can control the torque by a belt friction force, and non-elastic force pressure supplying pulley can control the revolution number, respectively so that the respective operating instructions may be processed in the lump to supply the informations to each operating device independently, and thereby simplifying and accelerating the control operation.
According to the first means for solving a problem in the present invention, said control device causes said processing unit to increase and decrease the compensation amount corresponding to said deviation amount from the input operating instruction in order to make said deviation substantially zero to convert it into the pressure operating instruction, whereby a pressure error of said elastic pressurizing force in said pressurizing device is restored and compensated.
According to the second means for solving a problem in the present invention, said control device causes said storage device to fine-adjust the desired selected value of said elastic pressurizing force during a period of transmission operation or transmission stop of said transmission device in order to forcibly enhance the efficiency or the safety rate with respect to frictional transmission, or to store in advance the adjustment amount for the reduction adjustment in order to suppress deterioration from high compression of the elastic member, and said processing unit forcibly increases an decreases said adjustment amount from the input operating instruction to convert it into the pressure operating instruction to impart a strengthening function to said pressurizing device.
According to the third means for solving a problem in the present invention, the error restoring compensation of the elastic pressurizing force and the forcible reduction adjustment of said elastic pressurizing force selected value in order to suppress deterioration of the elastic member are carried out, and the restoring compensation of the pressure error of said elastic pressurizing force is executed when said adjusting operation takes place to update the compensation amount when the transmission operation newly takes place for the high accuracy control.
According to the fourth means for solving a problem in the present invention, the compensation amount according to the deviation between a detected value of the revolution number of the secondary pulley or the speed ration of the transmission and a predetermined selected value of the output revolution number detector of said pulley or the speed ratio detector is applied to the pressure operating instruction.
The fifth means for solving a problem in this invention is to arrange the first and second drive sources independently connected to the first and second pressurizing devices, and thereby the operating instructions signal-processed on the side of the control device are supplied directly or indirectly.
The present invention is not limited merely to the wet type transmission device of a constant horse power transmission type having a large capacity for use with vehicles, but the present idea can be also applied to general industrial machineries having a small capacity as well as the dry type variable speed transmission irrespective of capacity. Particularly, the present invention makes of merits and demerits of the elastic device and the belt when the high pressurizing force generated by compressing the elastic device in series is applied to the pulley and the belt, and so, the present idea may be applied to the constitution that one of the pulleys holds the belt between two disks, and the other pulley is of not only the similar variable speed sheave but also the constant speed ratio sheaves of other types, and to a mere constant speed ratio transmission device. Further, not only in the case where the elastic force and the non-elastic force are applied to the secondary pulley and the primary pulley, respectively, but also in the case where conversely, the non-elastic force and the elastic force are applied to the secondary pulley and the primary pulley, respectively, the constant horse power transmission and the constant torque transmission can be achieved easily in a single machine. Also in this case, the frictional torque and revolution number of the secondary pulley can be maintained with high accuracy for a long period of time by the compensation measures and adjustment measures similar to the present example. Now, a tension type belt may be used instead of the compression type of the present embodyment.
The program control termed in the present invention includes a conception of a recent programmable control (PLC), in which adjustment and control are sequentially done in accordance with the change in a pressurizing force selected value programmed in advance in a storage device according to the change in the input manipulated variable.
The generated error of the pressurizing force results from various causes such as the deformation and deterioration of the elastic member or the belt, the error when materials or the like are manufactured, and peripheral temperature for use. To collectively restore them by one compensation, it is necessary to widely design the sliding displacement amount of the compression device in advance since the pressurizing device changes in zero and span positions. The elastic device may be added only one of the safety rate and the efficiency during the transmission operation as the strengthening adjustment, and may be applied with the additional function for applying the pressurizing force in excess of the maximum pressure P max or not more than the minimum pressure P min in the secondary pulley single shaft torque control mode. The pressure detector may convert the pressurizing force into other state amounts such as a position change other than the fluid pressure.
The single pressurizing with respect to the secondary pulley through the elastic device itself is possible during transmission operation or stoppage of the transmission unlike the primary pulley, and can be applied irrespective of the primary pulley and independently. In the constant horse power speed change gear, the pressurizing force can be reduced in the high speed rotational region. Therefore, where the elastic device or the belt can substantially suppress the settling deterioration or the deformation and deterioration even in the reduction state, it can be utilized as the substantial compression releasing measures of the elastic member according to the operating instruction.
Since the elastic pressurizing force of the pressurizing device may be applied between the pulley and the main body, arrangement order and locations of the elastic device and the compression device therebetween can be suitably changed according to the design, and where they are placed in the non-rotational state in terms of operation, rotation separating bearings may be disposed between the pulley, the compression device, the elastic device, and the main body. In the elastic device and the compression device are present a slider, a sliding unit, and a pressure transmission device as similar members, which may be jointly used with other members or subdivided and may be replaced by members such as disks of the pulley, and the main body according to the design. However, suitable changes are included in the scope of the present invention as long as they remains in mere selection and design of members.
The elastic device may be of a single elastic member, a kind of which is not limited to a wavy plate-like spring such as a dish spring but other forms such as a coil spring may be employed. Further, compression forms of the elastic deice are not limited to the continuous linear pressurizing characteristic by way of the simultaneous drive of a plurality of springs juxtaposed concentrically, but the pressurizing characteristic may be of the non-continuous stepwise characteristic by individually urging the respective elastic members with respect to the compression displacement, or of the non-linear continuous curve characteristic. Correction adjustment and compelled adjustment of an error in manufacture and an error in deterioration of the elastic member are simple measures in the case where the pressurizing characteristic is the linear characteristic.
The compression device may be a normal trapezoidal screw, and is not limited to a winding sliding mechanism comprising a displacement mechanism for converting rotation to sliding like a rotational cam, but a fluid pressurizing and sliding mechanism like a hydraulic cylinder may be employed. As long as the device is a jack mechanism having a pressurizing ability, a driving source may be an electric type or a fluid pressure type, and the installation place may be also a non-coaxial position or, rotational or non-rotational is available. As the first compression device, an example is disclosed in which a speed change displacement amount L01 of a secondary pulley and a compression displacement amount L02 of an elastic device are moved by the total displacement amount L0 (=L01+L02) with a single ball screw, but the compression device and its urging control device may be provided individually as long as they operate synchronously each other. When the compression amount of the elastic device need be further reduced, a compression displacement amount L03 of the elastic member itself may be provided separately.
The displacement amount L0 on the secondary pulley side required is about two times or so of the displacement amount L1 on the primary pulley side. Since the rotational operating direction as well as the operating amount are different according to the respective cases, well-known elements such as a winding pitch, a rotational direction, a revolution number of the compression devices, or a pressurizing direction of a threaded groove (right-hand thread, left-hand thread), and a speed ratio of the gear transmission may be suitably selected according to the design. As the driving source, there is used an AC or DC servo motor provided with an error signal transmission impeding means having self-lock functions of a reversible motor, that is, an anti-rotation brake mechanism and an anti-overrun function, but when the step motor itself performs the function of the preventive means, an open-loop drive may be done. In a trapezoidal screw and so on, a frictional resistance of metals surfaces is well-known to have such a self-lock function in itself. And also mechanical motors such as fluid or hydraulic motors may be applied.